Scattered applause broke out as a dark-skinned man in a grubby purple shirt took the stage and coughed nervously into the microphone in Change Square, the epicentre of the uprising that felled President Ali Abdullah Saleh and now a popular gathering spot for political debate.

"Institutionalized by the government and normalized by the people. We are Arabs, Muslims, Yemeni citizens, like you," said Nabil Al-Maktari, jabbing a finger at the crowd, his voice rising in anger.

"So why are we made to feel inferior? Why are we treated like slaves? I came to this square because I wanted to feel equality. Instead I find discrimination in every corner.

"This is racism in its worst form," he said.

The experience of helping to force Saleh from office after 33 years has energised some of Yemen's least powerful, including minorities and women, to try and change their fate. But dismantling rigid social structures may be even harder than bringing down an autocrat.

Maktari is one of those Yemenis known as the Akhdam, or "servants," and had been invited by the camp's stage committee to deliver a speech on Yemen's revolution and equality.

He was the first member of the Akhdam to set foot on the stage since it was assembled by protesters almost a year ago.

Distinguished by their African features and the jobs they perform - notably cleaning the streets - the Akhdam are so marginalised that they have been compared by anthropologists who study Yemen to the "untouchable" caste of India.

Widespread prejudice places the Akhdam at the bottom of Yemen's social ladder without specifying what makes them different beyond the colour of their skin and the menial tasks they perform.

Jamal Al-Obeidi, a secondary school mathematics teacher amongst those listening to Maktari's speech in early March, expressed typical views in answer to a reporter's questions.

"I have nothing against him," he said. "I would talk to him in the street, I might give him some of my money, but I would not invite him to my home. He is a Yemeni, but he is also a Khadim (servant). God meant for it to be that way."

Demeaning myths, inherited over generations, have helped entrench this way of thinking. Many Yemenis, asked about the origins of the Akhdam, say they are descendants of Ethiopians who crossed the Red Sea to conquer Yemen before the arrival of Islam some 1,400 years ago, and that makes them outsiders in their own country.

Prevailing prejudice holds that the men are lazy and unscrupulous, unfit for respectable work; the women, unclean and promiscuous, scrounge off the generosity of others, the conventional wisdom goes.

"If a dog licks your plate you should clean it," advises a proverb, "but if it is touched by a Khadim, then break it."

RUBBISH AS TOOL OF PROTEST

Yemen's 1962 revolution, which ended a 1,000-year-old Islamic principality and sought to implement a republic based on equality between citizens, officially abolished ancient status categories but the Akhdam retained theirs.

Working as house servants, emptying mosque latrines and, more recently, collecting the country's garbage, the Akhdam, most of whom live in fetid slums on the outskirts of the capital, are all but invisible to most Yemenis.

The protests against Saleh that broke out last February dragged them into the public sphere, perhaps for the first time.

On March 3, hundreds of Akhdam street-cleaners encircled the chief prosecutor's office in Taiz, demanding that a Yemeni police officer be brought to justice for what they claim was the racially motivated murder of a street-cleaner.

Demonstrator by day, street-sweeper by night, Shaefi Al-Shami was one of hundreds of Akhdam who joined the pro-democracy movement. He camped out in a small, red tent along with thousands of others in Change Square.

Despite being on crutches - he still has shrapnel lodged in his shin after he was caught in the crossfire during a sniper attack on protesters in Sanaa last March - Shami was instrumental in organising a nationwide strike last month amongst the country's street-cleaners, largely Akhdam.

That workforce performs one of the lowest-paid jobs in a poor country, without contracts working for local municipalities, subject to dismissal or denial of pay at the whim of the authorities.

By day three of the strike, with the capital swimming waist-high in piles of festering garbage, the authorities caved in, paying each of Sanaa's 4,000 street cleaners 15,000 rials to return to work and promising to make them permanent staff of the civil service.

Shami says that if the promise, delivered to them by Prime Minister Mohammed Basindwa, is not fulfilled by 15 March, they will do the same again.

"I think the strike reminded people of just how reliant they are on us, people were having to burn trash on their doorsteps just to get in and out of their houses," he said.

BURIED BY NIGHT

The military clashes that followed the eruption of protests against Saleh fed fears of a civil war, and led the country's wealthier Gulf neighbours, with U.S. backing, to engineer the succession of the president by his deputy.

The new president, Abd-Rabbu Mansour Hadi, will work with a government that includes opposition parties but also leaves Saleh's relatives in key positions in the military. It has also ruled out prosecution of the former president and his allies for the death of hundreds of demonstrators.

In the view of many protesters, the pact rewards a political elite that appropriated their cause and has ruined the prospect of real change.

Salwa Usman, a haggard, 60 year-old Akhdam mother, living in Mahwa Aser slum, a warren of tin-huts swimming in a sea of mud and raw sewage on the outskirts of the capital, is not optimistic.

The youngest of her nine children, who all work as street beggars, died last week from Hepatitis E, a water-borne viral disease that interferes with the functioning of the liver.

"We buried him in the Bani Hewat graveyard at 3:00 a.m., before sunrise," said Usman. "If others saw us they would say he was too dirty to be buried next to their dead."

(Editing by Joseph Logan and Sonya Hepinstall)

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